This invention relates to an exhaust system for small vessels and more particularly to an improved exhaust system for a small vessel that will insure against the entry of water into the exhaust ports of the engine.
In many instances, a vessel is powered by an internal combustion engine and the exhaust gases from the engine are discharged to the atmosphere through an underwater exhaust gas discharge. When this is the case, there is always a problem that water from the body of water in which the watercraft is operating may enter the engine through the exhaust system. This problem can be encountered even when an above the water exhaust system is employed if the watercraft reaches an unnatural condition, such as being overturned or capsized. Furthermore, it is the normal practice with water cooled internal combustion engines to discharge the cooling water from the engine cooling jacket into the exhaust system at some point before its discharge to the atmosphere. The advantage of discharging the cooling water into the exhaust system is that this serves to cool and silence the exhaust gases. The problem of water entry into the engine with such arrangements is also always prevalent.
Devices have been proposed wherein there is a check valve in the exhaust system that is intended to reduce the likelihood of the water entering the exhaust ports of the engine. However, most of these arrangements employ a check valve that is gravity closed and is opened by the exhaust gas pressure. As a result, this type of valve presents certain back pressure to the engine which can adversely affect performance.
Furthermore, even if a valve is employed in the exhaust system the entry of water into the exhaust system into proximity with the valve can cause the valve to inadvertently open at the wrong time. For example, if the valve is buoyant and the water is such that it tends to open the valve, the water can flow back into the exhaust port.
It is, therefore, a principal object of this invention to provide an improved arrangement for controlling the exhaust gases of a watercraft.
It is a further object of this invention to provide a control valve for the exhaust system of a vessel that will insure that water cannot enter the engine through its exhaust ports and wherein the valve does not create excess back pressure in the system.
It is a further object of this invention to provide a gravity operated exhaust control valve for a watercraft that is normally biased by gravity to an open position and which will close in the event the watercraft assumes an abnormal condition so as to avoid the likelihood of water entering the engine through its exhaust ports.
It is a further object of this invention to provide an improved arrangement for drawing water out of the exhaust system in the event that it enters the exhaust system due to an abnormal condition of the watercraft upon the return of the watercraft to its normal condition.